Combination device of the IC connection device and the main board

ABSTRACT

A combination device of the IC package connection device and the main board comprises a socket and a main board. The socket has a holding assembly which is placed on the top surface of the socket. The holding assembly connects to the external IC package electrically and the socket has a plurality of solder balls. The solder balls are placed on the bottom surface of the socket and connect to the holding assembly electrically. The socket is stable on the top surface of the main board and connects to the main board electrically. The positions of a plurality of PTHs in the main board are corresponding to the plurality of solder balls. The totally melting temperature of the solder balls is higher than that in prior art in order to make the solder balls be in controllable semi-solid state in solder reflow step. And a part of the solder ball will flow into a part of the PTH in order to form the mushroom-shape structure having an upper-mushroom part on the top surface of the main board and a lower-mushroom part flowing into the part of the PTH.

BACKGROUND OF THE INVENTION

[0001] (a) Field of the Invention

[0002] The present invention relates to the combination device of the ICconnection device and the main board. Especially, the present inventionrelates to a main board which is suitable to combine one of thepin-style socket and the ball-style socket.

[0003] (b) Description of the Prior Arts

[0004] For long time in prior art, there are two basic methods to placeIC package on main board. One is to solder firmly the IC package on themain board but the IC package is not replaceable. The other method isthat the IC package is replaceable, so the IC package can be replacedwhen necessary. Most of time, the replaceable combination device of theIC connection device and the main board is used when the IC device needsto be upgraded, the IC device itself needs to be replaced or in somecases that need expensive IC device. The replaceable IC device is usedwhen one of the devices on main board is broken or needs to be replacedbut the rest of the components on the board still in good condition, thecombination device of the main board and the socket of the CPU is a bestexample.

[0005] Please refer to FIG. 1 and FIG. 2, which showing a conventionalreplaceable combination device 10 of the main board and the socket of ICdevice in prior art. In prior art, an IC device 11 has pins 111, and themain board 12 has a socket 13 with many pin holes 131 in order toconnect each other in better electrical condition. There are two basicmethods to seal down the IC device 11, one is called lead frame and theother is BGA. In recent years, another method called flip chip BGApackaging has been used more often in sealing high-numbered pins ICpackage. FIG. 1 shows the basic components which comprising an IC chip112 placed on one side of the substrate 113 by flip chip method. Severalsolder balls 114 are placed on the other side of the substrate 113,which connecting the IC chip 112 and the substrate 113. The other sideof the IC chip 112 has a heat sink 115. For the pins 111 is not hardenough, and it is easy to be broken during replacing. And for the pins111 is not easy to connect the solder 114 firmly. So, before beingsoldered to the solder ball 114, it has to be placed on an interposer116 with modeling technology.

[0006] In order to provide the function, the pins 111 of the IC device11 will be placed. The socket 13 in prior art comprises a socket base132 with a plurality of holes 131 soldered on the main board 12, asliding board 133 which can slide linearly and a long levering bar 134placed aside the socket base 132 to be used to move the sliding board133 in a micro manner. The electrically conducting pad 137 is placed inevery pin hole 131 of the socket 132. And the solder pad 135 is on thebottom part of the pin holes 131. The pin holes 131 are extended fromthe bottom part of the electrically conducting pad 137 in order to formthe PTH (Plated Through Hole) 121 in the main board 12 for pins 1371.The electrically conducting layer 122 is set in the PTH 121 of the mainboard 12 in order to connect with pins 1371 electrically. The positionof the contact pad 1221 and the PTH 121 on the upper surface of the mainboard 12 can be SMD (solder mask defined) or NSMD (none solder maskdefined. The pins 1371 and the electrical connection device 13 aresoldered on the main board 12 firmly by the materials 123 and 125 of thesoldering. The larger holes on the sliding pad 133 corresponding to thepin holes 13 are set. Rotating the long stick 134 along the axle 136 tobe parallel with the socket 132 will make the slider 133 move in micromanner and the pins 111 in IC package 11 be hold tightly in the pinholes 131. In order to take out the IC package 11, the long stick 134can be rotated to be horizontal with the socket 132, and then the pins111 can be released from the IC package 11.

[0007] Please refer to FIG. 3 which is the combination device 10 a ofthe main board and the electrical connection device of the replaceableIC package in prior art. Because the IC package 11 and the electricalconnection device 13 a in prior art are similar to the devices in priorart in FIG. 1, additional description of the detailed element and thestructure is not necessary, but shown in dashed lines. The maindifference in FIG. 3 is that the combination device 10 a is usingseveral solder balls 138 but not the pin-style structures. Instead ofPTH, the solder pad 126 is placed on the main board 12 a by solderreflow of the solder ball 138 of the electrical connection device 13 aand the solder pad 126 of the main board 12 a. We can solder on thesolder pad 126 firmly for the solder balls 138. The disadvantages inprior art are the intensity of the structure of the combination of thesolder balls 138 and the solder pad 126 is weaker because the solderballs 138 and the solder pad 126 combine in plane-contact style. Thedisadvantage will lead to the increase of the defect of the products. Orthe department of the solder balls 138 from the solder pad 126 will bepossible. And the stability of the electricity and the short-circuitcharacteristics will happen because the overflow of the solder balls 138in the solder reflow. In the same time, the co-planarity of thecombination of the electrical connection device 13 a and the main board12 a will be bad.

[0008] The pin-style electrical connection device in FIG. 1 in prior artand the ball-style electrical connection device 13 a in FIG. 3 in priorart will use the corresponding main board 12 and 12 a. Because the mainboard 12 a in FIG. 3 will not provide the PTH to apply the usage of thepin-style electrical connection device 13. The PTH 121 in the main board12 can apply the usage of the pin-style electrical connection device 13.The main board 12 with PTH 121 will be in solder reflow with theball-style electrical connection device 13 a according to the ratio ofthe Sn/Pb being 63/37 and the Eutectic temperature of the solder ballsbeing 183 degrees. The working temperature is changed according to thedifferent time period. The highest working temperature is 220 degrees.We can not provide the stable connection of the electricity and thefunction of the soldering firmly. So we will not find the both functionsof the ball-style electrical connection device 13 a and the pin-styleconnection device 13 which are applied to the same main board.

SUMMARY OF THE INVENTION

[0009] The primary aspect of the present invention is to provide thesame combination device of the main board and the IC package connectiondevice. We can apply the combination device to combine with one of theball-style electrical connection device and the pin-style electricalconnection device.

[0010] In another aspect of the present invention is to provide thecombination device of the main board and the IC package connectiondevice. By the way of changing the ratio of the Sn/Pb in solder balls onthe bottom surface of the socket of the ball-style electrical connectiondevice, the Liquidus temperature (totally melting temperature) of thesolder balls will be changed to a proper value (higher than the Eutectictemperature). Thesemi-melting state of the solder balls will not beempty in the PTH in the solder reflow of the main board with PTH and theball-style electrical connection device. A part of thesemi-meltingsolder ball will be putted in a part of the PTH in order tomake the solder ball be a mushroom-shape structure after the process ofsolder reflow to provide the good intensity of the structure of thecombination, the co-planarity and the yield of the product.

[0011] To achieve the purposes described above, one of the embodiment ofthe present invention comprises a socket and a main board. Said socketincludes the inputted assembly on the top surface of the socket beingused to connect with the IC package electrically and some solder balls.The solder balls are on the bottom surface and are corresponding to theinputted assembly of the socket. Several PTH are in the main board andthe positions of the PTH are corresponding to the positions of thesolder balls. The Liquidus temperature of the solder balls is higherthan the Eutectic temperature of the solder balls, Sn/Pb at ratio 63/37,in prior art. The difference of the Liquidus temperature of the solderballs will make the solder balls be controllable semi-solid state andmake a part of the—semi-solid state solder ball be able to input to apart of the PTH in solder reflow process. In order to let the solderballs be the mushroom-shape structure and the upper-mushroom-shape parton the main board and the lower-mushroom-shape part inputted in a partof the PTH.

[0012] The appended drawings will provide further illustration of thepresent invention, together with the description, serve to explain theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 shows the side view of the combination device of the mainboard, the pin-style electrical connection device and the IC packagedevice in prior art.

[0014]FIG. 2 shows the top view of the combination device of the mainboard, the pin-style electrical connection device and the IC packagedevice in FIG. 1 in prior art.

[0015]FIG. 3 shows the side view of the combination device of the mainboard, the ball-style electrical connection device and the IC packagedevice in prior art.

[0016]FIG. 4 shows the side view of the first embodiment of thecombination device of the main board and the IC package connectiondevice in the present invention.

[0017]FIG. 5 shows the side view of the second embodiment of thecombination device of the main board and the IC package connectiondevice in the present invention.

[0018]FIG. 6 shows the side view of the third embodiment of thecombination device of the main board and the IC package connectiondevice in the present invention.

[0019]FIG. 7 shows the side view of the fourth embodiment of thecombination device of the main board and the IC package connectiondevice in the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0020] The major object of the present invention is to change the ratioof Sn/Pb in the solder balls on the bottom surface of the ball-styleelectrical connection socket and is to increase the Liquidus temperatureof the solder ball. The solder ball will be in controllable semi-solidstate in order to avoid flowing out from the PTH to be emptied by thegravity when the main board with the PTH and the ball-style socket arein the process of solder reflow. A part of the PTH will be inputted by apart of the liquid solder material. And it will make the solder ball bea mushroom-shape structure after the process of solder reflow. The uppersurface of the main board and the lower-mushroom part inputted in a partof the PTH will be formed. The structure of the combination of thesolder ball of the mushroom-shape socket and the PTH of the main boardwill provide the better intensity of the structure of the combination.And we will make the main board with PTH be suitable in the pin-stylesocket and the ball-style socket.

[0021] In the following embodiments, we will describe the detailedmethods, the way of the operation, the effect and the othercharacteristics of the present invention.

[0022] Please refer to FIG. 4. It shows the side view of the firstembodiment of the combination of the main board and the IC packageconnection device in the present invention. The IC package 11 will beconnected and plugged in the combination device of the main board andthe IC package connection device. The assembly of the IC packagecomprises an IC socket 30 and a main board 40.

[0023] And the pins 111 in the IC package 11 are not the maincharacteristics in the present invention. So we just show it in FIG. 4by dashed lines.

[0024] The IC connection device 30 comprises a holding assembly andseveral solder balls 31. The IC connection device 30 is a ball-stylesocket 30. The holding assembly is placed on the top surface of thesocket 30 and is used to connect the external IC device 11 electrically.The solder balls 31 are placed on the contact pad 32 of the bottomsurface of the socket 30 and connect with the corresponding holdingassembly electrically. The material of the contact pad 32 can be NI, Au,Cu, chromium, Fe, Al, Ti, lead, Sn or the alloy.

[0025] The holding assembly of the socket 30 comprises the followingelements: (a) several pin holes 33 (b) several electrically conductingelements 34 (c) a slide cover mechanism 35. The pin holes 33 placed onthe top surface of the socket can be plugged in by the externalpin-style IC package 11. And we can remove the IC package 11 ifnecessary. The electrically conducting element 34 is corresponding thepin hole 33 and contacts the corresponding solder ball 31 directly. Andin the same time the electrically conducting element 34 can contact thepins 111 of the IC package 11. The spring contact pad 36 on the bottomend of the electrically conducting element 34 will provide the functionof the electrical connection in the process of soldering the solderballs 31 on the main board 40 in the embodiment. The slide covermechanism 35 is placed on the top surface of the socket by sliding. Inorder to hold the IC package 11 on the socket 30, we will slide theslide cover mechanism 35 in limited distance when the external pin-styleIC package 11 is plugged in the pin hole 33 of the socket 30. Becausethe slide cover mechanism 35 is similar to the structure of the slidecover mechanism 35 in FIG. 1 and is not the major characteristics of thepresent invention, so the detail description thereof is not necessaryhere.

[0026] The solder balls are composed of Pb/Sn, Sn/Cu, Sn/Cu/Ag, Bi/Ti,Au/Sn or other compositions in prior art. For the Pb/Sn solder ball, theratio of Sn is between 5 percent to 95 percent and Pb is between 95percent to 5 percent. The better ratio of Sn/Pb of the solder balls 31will be between 60/40 and 75/25 in the present invention. In prior art,the totally melting temperature of the solder ball is 183 degrees whichis the Eutectic point of Sn/Pb at ratio 63/37. However, in the presentinvention, the ratio is between 60/40 and 75/25, which will change thetotally melting temperature (i.e. Liquidus temperature) of the solderballs 31 to between 190 degrees and 195 degrees. In other embodiments ofthe present invention, we can mix other metals (such as Ag or Sb) in thesolder balls 31 to change the Liquidus temperature.

[0027] The socket 30 is combined with the upper surface of the mainboard 40 and connects to the main board 40 electrically. The main board40 comprises several PTH 41. The position of the PTH 41 is correspondingto the solder ball 31. The solder pad on the upper side of the PTH 41 isformed in order to connect the solder ball 31 of the socket 30. Theelectrically conducting layer 43 is placed in the inner surface of eachPTH 41. The SMD (or NSMD) 44 is distributed on the upper surface of themain board 40. The position of the PTH 41 is defined by SMD 44. And thesolder pad 42 of every PTH 41 is not covered by SMD 44 and is on theouter surface of the main board 40 to combine the solder balls 31 of thesocket 30.

[0028] The socket 30 is departed from the main board 40 and the solderballs 31 is the spherical before the solder reflow applying to thesocket 30 and the main board 40. Many other devices (such as resistor,capacitor or other components not shown in the drawing) and the socketof the main board 40 are will be in the same solder reflow process. So,the Melting point in the process can not be changed flexibly but has tobe limited around 220 degrees. In present invention, the Liquidustemperature of the solder balls 31 will be maintained higher than 190degrees, so the hardness of the solder balls 31 will be controlled andnot totally flow away from PTH due to gravity. Only a part of the solderballs 31 will flow into the part of the upper PTH 41 to make the solderballs 31 form the mushroom-shape structure shown in FIG. 4. Theupper-mushroom part on the top surface of the main board and a part ofthe lower-mushroom part in PTH 41 will be formed and the lower-mushroompart will contact the inner surface of PTH 41.

[0029] The mushroom-shape structure of the socket 30 and the main board40 can make the main board 40 which having PTH 41 combine the ball-styleelectrical connection socket 30. And the solder balls 31 will nottotally flow away from the PTH 41. Because the solder balls 31 will formthe mushroom-shape structure in the process of solder reflow, a part ofthe lower-mushroom part in PTH 41 will combine the PTH 41 of the mainboard 40 tightly. The contacting area will be increased and theintensity of the structure of the combination will be better. Thestability of the electrical connection will be better. The material ofthe solder ball will flow into the PTH when the material of the solderball is too much. In the present invention, the co-planarity of thecombination between the main board 40 having PTH 41 and the ball-styleelectrical connecting socket 30 will be better. The yield of the productwill be improved.

[0030] The several solder ball 45 will be placed in the positions of thebottom side of the main board corresponding to every PTH. The solderballs 45 will form the upside down mushroom-shape structure after thesolder reflow process. And the mushroom-shape structure will comprisesthe upper-mushroom structure on the bottom surface of the main board 40and the lower-mushroom part in the bottom part of PTH 41. Thelower-mushroom part of the solder ball 45 and the lower-mushroom part ofthe solder balls 31 will not contact each other in the embodiment. Inanother embodiment, the lower-mushroom part of the solder balls 45 willcontact the lower-mushroom part of the solder balls 31.

[0031] In the following embodiments, the same name and the same numberwill be used for the same devices as in the previous embodiments. Forsome similar devices, an English letter will be added for distinguishingpurpose.

[0032] Please refer to FIG. 5. The schematic shows the side view of thesecond preferred embodiment of the combination of the main board and theIC package connection device. The solder ball will not be placed on thebottom surface of the electrical connection socket 30 a in FIG. 5. Thepin-style part 37 will be extended from the bottom part of theelectrical conducting element 34 a to form the pin-style electricalconnection socket 30 a. The material of the solder ball 46 is Sn/Pb andthe ratio thereof is 63/37. The material of the solder ball 46 willfulfill in the PTH 41 of the main board. The main board 40 in FIG. 5 inthe present invention can combine the ball-style electrical connectionsocket 30 and can combine the pin-style electrical connection socket 30a.

[0033] Please refer to FIG. 6. The third preferred embodiment of thecombination device of the main board and the IC package connectiondevice in the present invention exists. The bottom part of the socket 30b in FIG. 6 will not be placed the contact pad but to form the severalcurve-shape concave in order to define the positions for the solderballs 31. And in the same time a small hole will be set in the springcontact pad of the electrically conducting element 34 b. the intensityof the combination of the solder balls 31 and the socket 30 b will beimproved in solder reflow when partial material of solder ball of thesolder balls 31 flowing in the small hole.

[0034] Please refer to FIG. 7. The fourth preferred embodiment of thecombination device of the main board and the IC package connectiondevice in the present invention is shown in FIG. 7. The several slantconcaves are formed on the bottom part of the socket 30 c withoutcontact pad.

[0035] Comparing with prior art, the combination device of the mainboard and the IC package connection device and the replaceable methodsin the present invention have the following advantages: (1) The singlemain board 40 having PTH 41 is suitable for the several kinds of thedifferent sockets 30, 30 a, 30 b and 30 c. The cost is lower and thedesign will be flexible. (2) In the combination structure of the mainboard 40 having PTH 41 and the ball-style socket 30 and 30 b with thesolder balls in FIG. 4 and FIG. 6, the lower-mushroom part of themushroom-shape solder balls 31 flows and inserts into partial upper partof the PTH 41 of the main board 40. The characteristics will improve theintensity of the structure of the device and the co-planarity of thesocket 30 b and the main board 40.

[0036] While the present invention has been shown and described withreference to a preferred embodiment thereof, and in terms of theillustrative drawings, it should be not considered as limited thereby.Various possible modification, omission and alterations could beconceived of by one skilled in the art to the form and the content ofany particular embodiment, without departing from the scope and thespirit of the present invention.

What is claimed is:
 1. A combination device of an IC package connectiondevice and a main board comprises: a socket comprises: a holdingassembly being placed on the top surface of the socket and connecting anexternal IC package device; and a plurality of the first solder ballsbeing placed on the bottom surface of the socket and connecting to theholding assembly electrically; and, a main board on the top surface ofwhich combining the socket and connecting the socket electrically, themain board comprises: a plurality of PTHs which positions beingcorresponding to the plurality of the first solder balls which flowinginto a part of the PTH to make the first solder balls form themushroom-shape structure with upper-mushroom part and lower-mushroompart flowing into a part of the PTH.
 2. The combination device of an ICpackage connection device and a main board of claim 1, wherein theholding assembly of the socket comprises: a plurality of pin holes onthe top surface of the socket, and being plugged in by an externalpin-style IC package device; a plurality of electrically conductingelements being placed in the pin holes and being able to connect to theplugged-in pin-style IC package electrically; wherein the plurality ofthe first solder balls being connected to the plurality of theelectrically conducting elements electrically.
 3. The combination deviceof an IC package connection device and a main board of claim 2, whereinthe holding assembly of the socket comprises: a slide cover mechanismwhich being placed on the top surface of the socket in sliding manner,when a pin-style IC package being plugged in the pin holes, the slidecover mechanism moving in a limited distance to hold the IC package onthe socket firmly.
 4. The combination device of an IC package connectiondevice and a main board of claim 1, wherein an electrically conductinglayer is set in the inner surface of each PTH to provide the electricalconnection to the lower-mushroom part of the first solder balls.
 5. Thecombination device of an IC package connection device and a main boardof claim 1, wherein a plurality of the second solder balls being placedon the bottom surface of the main board in the corresponding respectivepositions of PTHs, and each of the second solder balls being the inversemushroom-shape structure, and having an upper-mushroom part on thebottom surface of the main board, and a lower-mushroom part flowing intoa part of the PTH.
 6. The combination device of an IC package connectiondevice and a main board of claim 5, wherein the second solder balls willnot contact the corresponding first solder balls directly.
 7. Thecombination device of an IC package connection device and a main boardof claim 5, wherein the lower-mushroom parts of the second solder ballscontact the corresponding lower-mushroom parts of the first solder ballsrespectively.
 8. The combination device of an IC package connectiondevice and a main board of claim 1, wherein a solder mask is distributedon the top surface of the main board to define the positions of the PTHsto make the PTHs be uncovered by the solder mask.
 9. The combinationdevice of the IC package connection device and the main board of claim1, wherein the first and second solder balls are composed of the alloyof Pb and Sn, in which the ratio of Sn is between 60 percent and 75percent, and the ratio of Pb is between 40 percent and 25 percent. 10.The combination device of the IC package connection device and the mainboard of claim 5, wherein the first and second solder balls are composedof the alloy of Pb and Sn, in which the ratio of Sn is between 60percent and 75 percent, and the ratio of Pb is between 40 percent and 25percent.
 11. The combination device of an IC package connection deviceand a main board of claim 1, wherein at least one external electronicdevice is placed on the main board.
 12. A combination of an IC packageconnection device and a main board comprises: a pin-style socketcomprises: a first holding assembly being on the top surface of thepin-style socket and being used to connect an external IC packageelectrically, and a plurality of pins being combined on the bottomsurface of the pin-style socket and connecting to the first holdingassembly electrically; a ball-style socket comprises: a second holdingassembly being on the top surface of the ball-style socket and beingused to connect an external IC package electrically, and a plurality ofthe first solder balls being combined on the bottom surface of theball-style socket and connecting to the second holding assemblyelectrically; and a main board which comprises a plurality of PTHs;wherein the corresponding positions of the plurality of PTHs and theplurality of the first solder balls and the plurality of pins are thesame, the combination device of the IC package connection device and themain board is formed by combining the main board and one of thepin-style socket and the ball-style socket in order to make the mainboard be suitable for both sockets: and when the main board andpin-style socket being combined, each pin in the pin-style socket isplugging in the corresponding PTH of the main board; when the main boardand ball-style socket being combined, a part of each first solder ballwill flow into a part of the PTH in order to make the first solder ballform a mushroom-shape structure having an upper-mushroom part on the topsurface of the main board and a lower-mushroom part flowing into thepart of the PTH.
 13. The combination device of an IC package connectiondevice and a main board of claim 11, wherein the second holding assemblyof the ball-style socket comprises: a plurality of pin holes being onthe top surface of the ball-style socket in order to be plugged in by anexternal pin-style IC package; a plurality of electrically conductingelements being placed into the corresponding pin holes and beingconnected to the external pin-style IC package electrically; wherein theplurality of the first solder balls respectively connecting to theplurality of the electrical conducting elements electrically.
 14. Thecombination device of an IC package connection device and a main boardof claim 12, wherein the second holding assembly of the ball-stylesocket further comprises: a slide cover mechanism being placed on thetop surface of the ball-style socket in sliding manner when the externalpin holes of the ball-style socket is plugged in the pin-style ICpackage by the way of moving the slide cover mechanism in a limiteddistance to hold the external pin-style IC package firmly on theball-style socket.
 15. The combination device of an IC packageconnection device and a main board of claim 11, wherein an electricallyconducting layer is set in the inner surface of each PTH of the mainboard.
 16. The combination device of an IC package connection device anda main board of claim 11, wherein, when the ball-style socket combiningwith the main board, a plurality of the second solder balls will beplaced on the corresponding positions of PTHs respectively on the bottomsurface of the main board, and each second solder ball has an inversemushroom-shape structure having an upper-mushroom part on the bottomsurface of the main board and a lower-mushroom part flowing into a partof the PTH upwardly.
 17. The combination device of an IC packageconnection device and a main board of claim 15, wherein the secondsolder balls will not connect to the corresponding first solder ballsdirectly.
 18. The combination device of an IC package connection deviceand a main board of claim 15, wherein the lower-mushroom parts of thwsecond solder balls contact to the corresponding lower-mushroom parts ofthe first solder balls respectively.
 19. The combination device of an ICpackage connection device and a main board of claim 11, wherein a soldermask is distributed on the top surface of the main board to define thepositions of the PTHs to make the PTHs be uncovered by the solder mask.20. The combination device of an IC package connection device and a mainboard of claim 11, wherein the first and second solder balls arecomposed of the alloy of Pb and Sn, in which the ratio of Sn is between60 percent and 75 percent, and the ratio of Pb is between 40 percent and25 percent.
 21. The combination device of an IC package connectiondevice and a main board of claim 15, wherein the first and second solderballs are composed of the alloy of Pb and Sn, in which the ratio of Snis between 60 percent and 75 percent, and the ratio of Pb is between 40percent and 25 percent.